Botox for TMJ: Not an Open & Shut Case

FIRST THOUGHTS

Having now injected the jaw musculature with Botox over the last ten years, some valuable insights have been gained. Most importantly, I still feel strongly that the use of Botox injections should not be a first-line treatment effort for patients suffering with temporomandibular problems inclusive of jaw muscle pain, spasm, and/or limited jaw motion. These problems are predictably handled with other therapeutic modalities that may start with education, behavior modification, jaw exercises, oral appliances, medications, and/or physical therapy. The results with these interventions is not only predictable, but provide relief that is often long-standing in nature and does not require ongoing patient care and surveillance.

In addition, there does not appear to be a primary role for Botox injections to manage painful and clicking temporomandibular joints. These problems are often inflammatory and commonly relate to the loss of structural integrity in the supporting?ligaments in the TM joints. These problems, therefore, are not readily managed with Botox injections.

MUSCLE PAINS…NOT ALL THE SAME

When it comes to muscle pain, particularly muscle pain that has not been responsive to the common treatment options listed above, it becomes important to distinguish between muscle pain that has a localized pattern and muscle pain that has a referring character. Localized muscle pain means that the muscle pain is felt only at the site of palpation. Referring muscle pain is characterized by pain that spreads beyond the point of palpation.

My experience has been that localized muscle pain can be treated effectively with Botox; but success with pain that spreads beyond the point of muscle palpation does less well on a routine basis. For instance, if a jaw muscle is palpated and pain spreads to the ear or a tooth, it is less likely that this type of problem can be handled effectively with Botox. On the other hand, if a jaw muscle is palpated and pain remains specifically at the palpation site, it is more likely that Botox will be helpful.

This is because the pain that spreads beyond the palpated muscle and is felt in an ear or a tooth is the end result of what is called central sensitization. In such cases, nerves in the muscle area that was touched send signals through the nervous system to the brain. Once that happens, pain can be referred or projected to innocent tissue. This typically occurs in patients with longstanding pain problems and can be an important tipoff that Botox is not an ideal treatment strategy.

One other tip is this: I have found Botox to be most helpful when there is evidence of muscle hypertrophy in the masseter and or temporalis region. The hypertrophy indicates that muscle tissue has been overworked with the end result being bulging muscle profiles when the teeth are clenched. Patients who have jaw muscle pain without hypertrophy have been less responsive to Botox injections.

TREATMENT STRATEGIES

In many cases, if pain is reduced after a particular muscle has been injected with Botox, it is likely that one or more repeat injections somewhere between three and four months later will be required to maintain symptom relief. In particular, if the causative or perpetuating factors are not addressed, Botox will provide only short-term benefit. Therefore, Botox is usually a complementary source of care and must be utilized in conjunction with other therapies.

Botox is not a cure, as we are not typically treating a disease process. But in the right scenarios gives nature a chance to restore healthier muscle physiology.

Determining the amount of Botox to be utilized to address pain has also been tricky business. At this point in time it has not been absolutely determined what amount of Botox is necessary to produce a beneficial response. From my experience, it appears that somewhere between 15 and 25 units are required in the masseter muscles and 10 to 15 units in the temporalis muscles. I believe that injecting both of these jaw-closing muscles bilaterally is important.

As previously mentioned, it is quite likely that multiple injection sessions will be necessary to adequately confront the persistent pain in patients requiring this type of intervention. If these patients do not participate in the process of identifying why their jaw muscles are in trouble, the outcome of this treatment strategy may be limited. In addition, despite the fact that oral appliances may not have been totally effective in helping this patient population when used alone, I continue to recommend that oral appliances be used during the sleeping hours.

WHY BOTOX CAN BE EFFECTIVE

What should be understood is this: the pain reduction that occurs with Botox muscle injections may not only have to do with reducing the force of muscle contraction, but also in reducing the release of certain chemicals that are tied to the experience of pain. Recent research has revealed that Botox diminishes the release of pain producing neuropeptides, and if this continues over an extended period of time, nerve thresholds are improved. Along with reducing the strength of muscle contraction, this added benefit is likely to be playing a role as well.

USES BEYOND PAIN

Also worth mentioning is that many patients now come to my office with the goal of having their jaw muscles reduced in bulk. Reducing the bulk of jaw muscles can, in fact, be achieved with a series of Botox injections given three months apart. The slimming of jaw muscles, however, requires a somewhat different approach than that used strictly for pain. When addressing the cosmetic desires of patients, Botox is typically injected along the length of the muscle (not just in the site of pain). These injections then require a bit more art in the technique as visualization of the desired result is necessary as part of the overall plan of injection therapy. Most importantly, photographs should be taken before treatment starts in order to obtain a sense of the improvement from Day One.

There comes a point, however, where the overuse of Botox can create significant atrophy of the jaw muscles and lead to a sunken-in facial appearance in the patient.

SUMMARY

Botox is here to stay as a therapeutic alternative to manage facial and jaw pain inclusive of that due to TMJ. On the cosmetic side there also appears to be a place for Botox to assist in re-contouring jaw muscles that are viewed as unaesthetic by patients presenting for care.

I welcome your thoughts.